In the exploration and production of oil and gas, drill pipe or a column of drill pipe (e.g., a drill pipe string) may be employed for a variety of purposes. On a drilling rig, the drill string is made up on the rig's platform. The drill string is run downhole and into the well bore. The drill string transmits drilling fluid (via mud pumps) and rotational power (via a Kelly or top drive) to the drill bit, which is part of a bottom hole assembly positioned at the end of the drill string. The drilling fluid is pumped down through the internal bore in the drill string, exits at or near the drill bit, and circulates back up the well annulus (void between the drill string and the well bore). The drill pipe string may also run casing, a liner, or a landing string downhole. The drill pipe string may also be used to work-over a hydrocarbon well. Drill strings can reach a length of 30,000 feet for a vertically drilled well and 35,000 feet for a deviated or horizontal drilled well.
The drill string includes a column of individual joints or segments of drill pipe threadedly connected together by threaded ends. A joint or segment of drill pipe may vary in length. Typically, the length of a drill pipe joint ranges from 30 feet to 33 feet. A joint or segment of drill pipe has a box member secured at one end and a pin member secured at the other end. The box member is internally threaded and adapted to receive the pin member of another drill pipe joint, which has external threads. Mating joints of drill pipe are interconnected via the threads to make up the drill string. The joints of drill pipe must be securely made up to prevent leakage, wobbling, or unscrewing. Typically, power tongs are used to transmit sufficient rotational torque to the pipe joints to ensure that the pin end is tightly threaded in the box end; this is called make-up torque. The amount of torque required depends in part on the specific frictional properties of the threaded connections. A higher friction coefficient means increased torque transmitting ability thereby lessening instances of tool joints unscrewing and having to be made up downhole. A lower friction coefficient with less torque transmitting ability may cause too much torque to be applied when making up the joints. Excessive torque could stretch or burst the box member or crack or break the pin member. This is undesired as drill pipe is expensive.
Pipe “dope” may be applied to the threaded connections of the joints to maintain a high coefficient of friction. The dope permits easier breaking down of the tool joints and helps prevent excessive make up. Despite the application of pipe dope, excessive make up and joint damage remains a problem. Moreover, the use of power tongs to make up pipe increases operational costs as additional equipment and personnel are required. The need exists for equipment and methods to connect drill pipe joints without rotating the drill pipe into itself.